Book Image

Mastering PLC Programming

By : Mason White
Book Image

Mastering PLC Programming

By: Mason White

Overview of this book

Object-oriented programming (OOP) is a new feature of PLC programming that has taken the automation world by storm. This book provides you with the necessary skills to succeed in the modern automation programming environment. The book is designed in a way to take you through advanced topics such as OOP design, SOLID programming, the software development lifecycle (SDLC), library design, HMI development, general software engineering practices, and more. To hone your programming skills, each chapter has a simulated real-world project that’ll enable you to apply the skills you’ve learned. In all, this book not only covers complex PLC programming topics, but it also removes the financial barrier that comes with most books as all examples utilize free software. This means that to follow along, you DO NOT need to purchase any PLC hardware or software. By the end of this PLC book, you will have what it takes to create long-lasting codebases for any modern automation project.
Table of Contents (25 chapters)
1
Part 1 – An Introduction to Advanced PLC Programming
6
Part 2 – Modularity and Objects
10
Part 3 – Software Engineering for PLCs
14
Part 4 – HMIs and Alarms
19
Part 5 – Final Project and Thoughts

Implementing the PLC code

Now that we have a design, we can implement the code. The code implementation should be relatively minimal. The first thing we are going to do is declare our function blocks. For this, we are going to create a folder named FunctionBlocks and use it to house the Oven, Alarms, and Door function blocks. When all the function blocks and methods are implemented, your tree should look like this:

Figure 15.14 – Function blocks

Figure 15.14 – Function blocks

Once you create the tree, you can start to implement the methods. The first set of methods you will want to implement are the methods of the PLC_PRG file.

PLC_PRG file

The first place we’re going to start implementing code is in the PLC_PRG file. Since it is our entry point, we’re going to put our starting logic here. In short, you should have your variables all implemented in the vars GVL at this point, except a reference variable for the Oven, Alarms, and Door classes, which will look...